Design optimization of abrasive jet decontamination nozzle for radioactively contaminated scrap metal based on CFD-DEM

This study presents an innovative design methodology for abrasive nozzles that integrates multi-software collaborative simulation with multi-objective optimization, aiming to significantly improve the overall performance of abrasive jet cleaning. A coupled CFD-DEM numerical model was developed to systematically investigate, for the first time, the inherent influence mechanisms of critical nozzle structural parameters—including throat diameter, contraction length, divergence angle, and total length—on both abrasive jet uniformity and nozzle wear resistance. Through response surface methodology, a multi-objective optimization model was constructed and solved, yielding an optimized nozzle configuration with an inlet diameter of Ф25 mm, throat diameter of Ф14 mm, divergence angle of 8°, and total length of 215 mm. Experimental validation confirmed that this optimized design synergistically enhances performance, achieving a 22.00% increase in abrasive jet core coverage while reducing maximum nozzle wear by 44.62%. Furthermore, this research establishes a multi-software integrated simulation and optimization framework, termed the “FLUENT–EDEM–MATLAB–ORIGIN–DESIGN-EXPERT” workflow, which provides a robust methodological paradigm with considerable engineering relevance for the design of high-performance gas–solid two-phase flow nozzles.